Safety device for high-explosive fuses and projectiles



ATTORNEY Jan. 26 1926.

P. D. VAN ESSEN sAFE EY DEVICE FOR HIGH ExPLpsIva FUSES AND PROJECTILES o m Filed May 15. 1924 INVENTOR WEE-sen A fx/ Patented Jan. 26, 1926.

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PIETER DANIEL VAN ESSEN, 0E HAAG, NETHERLANDS, ASSIGNOR TO BETHLEHEM STEEL GOMEANY, A CORPORATION OF PENNSYLVANIA.

SAFETY DEVICE FOR I-IIG-H-EXPLGSIVE FUSES AND PROJECTILES.

Application filed May 15, 1924, Serial To tell whom it may concern:

1. c it known that I, Pnrrna DANIEL VAN a subject of the Queen of the Netherlands, residing at Nassauple1n 20, Haag, Netherlands, have invented certain new and useful Improvements in Safety Dev ces for tligh l lxplosive Fuses and Tl'OJQCtIlGS, of which the following is a description.

Projectile fuses adapted to fire on nnpact broadly consist of a detonator component fired by percussion and of certain safety devices that are operable by the act on of set back, by the rotation of the pro ectile, by the differences of inertia in the componeuts, or combination of these factors, so as to guard against a premature firing of the detonator.

In order to intensify the wave of detonation initiated by the detonator and increase its velocity, it is customary to provide a booster charge or rcnfort of high explosive in sufiiciently close proxinutv to the detonator that the firing of the latter Wlll detonate the booster charge. Premature detonations, however, have been known to take place during handling and transportation, or in the gun, due to an inherent defect of the detonator itself and not to a faulty function of the fuse mechanism. Such defects may be caused by faulty manufacture of the detonator or the use of chemically unstable materials in the detonating composition. lVhatever the cause, it is evident hat any premature firing of the detonator, especially if the latter be in close propinquity to the booster charge, wlll result in the complete detonation of the main explosive charge in the projectile and the consequent serious damage to personnel and material. For this reason fuses have been designed so that the initial detonator is normally kept separate from the booster charge and is only brought into close proximity therewith by the operation of the fuse, when the projectile is actually fired from the gun. Fuses of this nature, however, involve the use of expansion chambers, wherein the gas pressure released on the firing of the detonator, when the latter is not 1n proximity to the booster charge, is dissipated in free space, so as not to effect the detonation of the booster charge. Other types of fuses involve the permanent separation of the detonator from the booster charge, communication of the detonation No. 713,512. Renewed March 6, 1925.

being effected by means of ports or channels normally closed and only opened by the mechanical operations of the fuse. WVhatever the means adopted and whether they be used for nose fuses or base fuses, mechancal complications of the fuse elements are involved and where expansion chambers are also necessary, materials of special physical properties must be used.

The propagation of a wave of detonation from one explosive body to another, not in actual contact with it, is substantially influenced by the nature of the intervening medium. The velocity of detonation through a solid body may be considered to he of an oroer similar to that of the velocity of sound, in which the elasticity of the intervening solid is a factor. I have found that materials of a yieldable or plastic nature, interposed between the detonator and the booster charge in a fuse, serve to effectively damp a wave of detonation coinniuuicated to them and that they are unable to further communicate said detonation except at a very much reduced velocity.

The object of my invention is, therefore, to utilize the damping effect of readily yieldable or plastic materials by using mate rials of this nature as an intervening shield between the detonator and the booster charge in a projectile fuse.

Figure 1 is an axial cross section of a fuse embodying my invention.

Figure 2 isa perspective view of the protective sheath 41.

To illustrate one possible application of my invention, in combination with a fuse and a high explosive projectile, I show in the accompanying drawing an impact fuse of the type described in my co-pending application, Serial No. 713514, filed May 15, 1924. In this drawing, I show the detonator casing 24 in its inoperative position in the center of the booster charge 40. The casing 24, which supports the detonator 28, is surrounded by a protective sheath of parafiin wax, 41, interposed between the detonator and the booster charge. The operation of the fuse, as fully described in my co-pending application, Serial No. 713514, filed May 15, 1924, is such that the detonator 28 is withdrawn forwardly out of the protective zone of the sheath 41 to a firing position. In this firing position, the detonator 28 is in close proximity to the forward and unprotected portion of the booster charge 40; this position being determined by the forward shouldering of the detonator body 21 of the closing plug 14.

In the event of the detonator being prematurely fired while within the protective zone of the sheath 41, the velocity of the detonation initiated thereby is sufficiently reduced by the damping influence of the protective sheath 41 to make it impossible to obtain detonation of a high order in the projectile. I

It will be evident to anyone skilled in the art that the use of protective sheaths of this nature can be applied to all types of nose fuses and base fuses, having an initial detonator and a booster charge. Said protective sheaths may be adapted to be themselves movable in relation to the detonator, so as to uncover't-he latter when in a firing position, or they may be fined immovably and the detonators may be withdrawable therefrom as in the case ofthe fuse herein referred to.

I do not limit my invention to the use ofv paraffin wax alone but intend it to embrace the use of any material of a yieldable or of a plastic nature, whether said material be resilient or not, for the purpose of exercising a damping effect on a wave of detonation. As examples of other materials that I consider suitable for the purpose, I mention, cerasin wax, gelatine, asphalt, bitumen, gums, as materials which are essentially yieldable but are not resilient. I also mention gutta percha as a material that is both yieldable and resilient.

Furthermore, I do not limit the application of my invention to any specific com bination of a fuse and a projectile. I may use-my protective sheath for the separation of the detonator from the booster charge in a fuse or for, the similar separation of the detonator charge in a fuse from the projectile charge. Also said protective sheath may be a component part of the fuse or a component part of the projectile itself;

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. In a projectile fuse, the combination of a booster charge, a detonating charge movable to armed and unarmed positions with respect to the booster charge, and a sheath of non-metallic material'positioned within the booster charge for separating the charges when the detonating charge is 'in unarmed position and serving to prevent the effective transmission of waves of detonation to the booster charge.

2. In aprojectile fuse, the combination of a booster charge, a movable detonating charge and a shield for separating the charges and dampening the propagation of detonating Waves to the booster charge in one position of the detonating charge.

3. In a projectile fuse, the combination of a booster charge, a movable detonating charge and a shield for separating the charges and serving to dampen Waves of detonation to prevent their effective propagation to the booster charge. 7

4c. In a projectile fuse, the combination of a detonator charge, a booster charge, and means for separating the charges in one position of said parts, relatively toeach other, to dampen the waves of detonation toprevent the effective propagation thereof to the booster charge.

5. In a fused projectile, the combination of a detonating charge in the fuse, a booster charge in the fuse, an explosive charge in the projectile and means for separating the charges in one position of said parts relatively to each other to dampen the waves of detonation to prevent the effective propagation thereof to the explosive charge.

6. In a projectile fuse, the combination of a booster charge, a movable detonating charge and a sheath of non-metallic. material for separating the charges in one position of the detonating charge.

7. In a projectile fuse, the combination of a booster charge, a detonating charge movable from unarmed to armed position Within the confines of the booster charge, and a non-metallic member separating the charges when the detonating charge is in its unarmed position.

8. In a projectile fuse, the combination of a booster charge, a detonating charge movable from unarmed to armed position within the confines of the booster charge, and an inert material imbedded in the booster charge and surrounding said detonating charge when the latter is in its unarmed position.

9. In a projectile fuse, the combination of a detonating charge movable to armed and unarmed positions, a booster charge pro vided with a cavity within which the detonating charge is movable, and a cup consisting of inert material, disposed within the cavity of the booster charge, and surrounding the detonating charge when the latter occupies its unarmed position for preventing the eifective transmission of waves of detonation to the booster charge.

In testimony whereof I hereunto affix my signature this 13th day of May 1924:.

PIETER DANIEL VAN ESSEN. 

